On Fri, 07 Dec 2007 14:42:00 -0500 Aaron Kulkis <[EMAIL PROTECTED]> wrote:
> Initially, i thought RISC was a crazy idea, compared to > the ultra-CISC VAX-11 instruction set...but then when I > read about the issues with page faults... I was almost > immediately convinced that yes indeed, the RISC guys did > have a very, very important point, and that the Clipper > chip and others weren't so crazy after all. Initially, the Digital Alpha supported VMS, Digital Unix (Tru64 Unix), and OpenVMS. There was a program (VEST) that could be used to translate a VMS application and library to run on the Alpha. The Vested application was both translated and emulated. Over time, the application actually needed less emulation. Floating point was an issue. The Alpha chip had native 64-bit IEEE format (sign bit, 11 exponent bits, 53 mantissa bits - there was 1 hidden bit) floating point hardware (with full IEEE being executed in PALcode or software). The VAX had a number of different hardware floating point formats so that most of the native VAX floating point formats were emulated on the Alpha. -- Jerry Feldman <[EMAIL PROTECTED]> Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9
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